Japanese knives are among the most iconic and coveted items for a culinary enthusiast. Their sharpness is legendary, their shapes elegant and refined. However, even among insiders, there is always much confusion and lack of accurate information.
In this article we will try to shed some light on the various types of Japanese kitchen knives, their proper use and maintenance, and how to choose them consciously.
It may seem trite rhetoric that to talk about Japanese kitchen knives one must bring up katanas and samurai. Yet the craftsmanship of Japanese blacksmiths has its roots deep in the Japanese Middle Ages. In that era, constant wars between feudal lords required constant production of swords. Artisans thus developed extremely refined metallurgical techniques.
In Europe, the use of thick armor required sharp, heavy weapons, used as clubs to stun the opponent or awls to pierce his defenses. In Japan, on the other hand, the fighting technique was faster and more agile, with lighter armor, and favored the use of the slashing sword. However, this led to a series of cascading technical problems.
Although light, the armor still provided some protection. For the blow to be effective, with a lightning-fast movement, the warrior had to “charge” it by raising the sword above his head and then plunging it with full force into the opponent. With a heavy sword, the movement would have been slow, making the attacker vulnerable. With these large movements, repeated in the many clashes of a battle, no matter how well trained in martial arts, the samurai would tire quickly. The sword therefore had to be thin to be light. However, reducing the thickness reduced its strength, and with too strong a blow it would break.
The technical solutions developed to find a compromise between all these needs were complex and ingenious.
As a raw material, blacksmiths used iron sands, which, due to its very low sulfur content, gave a stronger steel.
They then invented the assembly technique (tsukurikomi – 作り込み). Two or more types of iron with different carbon content and thus different mechanical properties were welded together to make the blade. The supporting structure of the sword was made of a relatively soft and flexible iron, thus able to absorb the stresses of blows. The cutting edge, on the other hand, was made of a harder and sharper steel.
With the same end in mind, gunsmiths developed the sophisticated differentiated tempering. Tempering is the operation in which the blacksmith makes the iron glow and then quickly immerses it in water. By a physical process, the sudden cooling hardens the metal.
In differentiated tempering, Japanese blacksmiths covered the blade with clay. The thickness of the clay was greatest on the ‘back’ of the sword, and became thinner as one approached the edge. When they immersed the glowing blade in water, the exposed wire cooled immediately, thus becoming harder but also more brittle. The sides of the sword that were insulated from heat by the thicker layer of clay cooled more slowly, making them more flexible and strong.
Such was the prestige associated with the sword that the finest models were considered true works of art, displayed as a symbol of power and never used in battle. A sword was valued not only for its technical and functional qualities, but also for the elegance of its lines.
Of course, there is a big difference between a katana and a kitchen knife, but the story serves to illustrate how the Japanese take steel and “sharp things,” even kitchen knives, very seriously.
Not a little of the long metalworking tradition of master katana smiths has gone into the making of handcrafted Japanese knives. Forging techniques developed for traditional swords are employed in the making of quality knives. The most common is the assembly of different steels so as to have more or less flexibility and hardness depending on the points of the knife. Harder for the blade that must be sharp, more flexible for the main body that must absorb vibrations and torsions.
The most expensive knives (even thousands of euros) are still made from ferrous sands.
Purchasing a Japanese Kitchen Knife
In recent years, with the fashion for Japanese cuisine, sushi first and foremost, we are beginning to see Japanese kitchen knives displayed in homeware stores, supermarkets, and cutlery shops. However, at best, these are knives perhaps produced in Japan but made industrially for export. At worst they are imitations, made you know where, with some flashy ideogram printed on them. However, for fans of cooking in general, and Japanese cooking in particular, there are a few things to know about Japanese knives before making a purchase.
Stainless VS Steel
First of all, it is most important to know that a traditional Japanese knife is made of a steel that rusts.
Stainless steel is an excellent material for making pots, pans and vessels, somewhat less so for making sharp blades. In fact, stainless steel does not reach the sharpness levels of other types of carbon steel. A traditional Japanese knife left soiled with onion and fish guts in the sink, already after half an hour may show specks of rust here and there.
This is not a sign of poor quality, but rather of the fact that the blade is made with cutting as a priority, not convenience of use. This is why a real Japanese knife should be washed as soon as possible when you finish using it, possibly with a rough sponge, with the knife resting on a flat surface, and with movement perpendicular to the edge and toward the blade, not against it. In the opposite direction, in addition to ruining the edge, you would risk making your fingerprints disappear with copious spillage. The knife should then be dried well with a cloth (watch your fingers) and stored in a safe place. No dishwasher then. It is a hassle, but slicing even an onion with such a knife is an experience that, for a culinary enthusiast, should be tried at least once in a lifetime.
Those who, on a trip to Japan, have gone to eat sushi in a traditional restaurant may have noticed that every cook always has a tea towel handy, which he passes over his knife again and again. It is not only to clean it of fish and rice residue between cuts, but also to keep it as dry as possible.
If you are a restaurant professional, you should know that a traditional Japanese knife is not up to standard in European countries. The steel from which it is made, precisely because it can rust easily, is not certified for food use. Therefore, be careful about keeping it in the kitchens of your establishments because you could face steep fines.
In Japan the problem does not arise because it is taken for granted that a professional cook knows how to use and properly maintain his or her work tool.
That is precisely why the Japanese, who do not want to give up a sharp blade, invented ceramic knives a few decades ago. Which cut almost as well as a steel knife, but do not rust and need less care than traditional knives. The only problem is that since ceramic is brittle they can break.
Sharpening a Japanese Kitchen Knife
Another thing about Japanese knives that is important to know before making a purchase is that they need to be sharpened. This may seem like an obvious point, but how many people have kitchen knives at home that they have never sharpened? Of course even the cheapest of knives if sharpened will cut, but the level of sharpening that can be achieved with a Japanese blade is something else entirely.
With daily use one would need to refresh the edge at least once a week, resorting then to professional sharpening once a year. And here comes the sore point since most of our local knife grinders, by now accustomed to ordinary stainless steel knives, mostly have power grinders. After one pass under such torture, a Japanese knife can be safely thrown away. In the different types of knives should be sharpened differently (more details below).
Sharpening should be done strictly by hand with a water stone. You should have at least a couple of different grits, 800/1000 for coarse work, and 1500/2000 for finishing. It is no accident that Japan is among the leading manufacturers of sharpening stones. Stones must always be perfectly flat to ensure optimal sharpening. With continuous use, sharpening stones develop a screwing in the center where passes are most frequent. It is therefore important to grind them regularly with special tools. If you bought a knife in Japan, to avoid any nasty surprises, check very carefully how your knife grinder works before taking it to be sharpened.
Another thing to know about Japanese kitchen knives is that they are quite expensive. A handcrafted knife precisely because of the special treatments the steel must undergo to acquire certain characteristics, for sharpening and for certain finishes undergoes much of its processing by hand, in a whole series of obligatory steps. The prices are therefore consequential. For an average knife it is difficult to go below 8,000 yen, between 60 and 80 euros depending on the euro/yen exchange rate level. Considering transportation, taxes, mark-ups, when it arrives in the window of a European store you can expect to pay between 150 and 200 euros. As for maximum prices, however, as always in Japan, there is virtually no limit upward. You can easily find knives worth several thousand euros.
The bottom line is that it is not enough that it has a Japanese shape and a few ideograms printed on the blade to have a knife that cuts properly. So beware of what you find in household stores, even of a certain level, or online in our neck of the woods.
Types of Japanes Kitchen Knives
Let us now see what are the main types of knives you can find in a knife store in Japan. There are endless varieties, each with the appropriate shape, established and codified over centuries of use, for every human activity, not just cooking. For a knife enthusiast, the craft stores in certain neighborhoods of Kyoto and Osaka become traps from which one comes out with a lightened bank account. There are knives for meat, fish, vegetables, for cutting chestnuts or skinning eels, for quartering, filleting, slicing large or small fish, oysters, you name it. The strangest are the ones for cutting soba (buckwheat noodles), which could very well be used by us to make noodles by hand.
With its unusual shape it is the most classic of Japanese kitchen knives, the most stereotypical, the one that every self-respecting gaijn wants to bring back from a trip to the rising sun and then flaunt it with friends at the first opportunity, perhaps to cut shavings of parmesan cheese, as I sadly saw done at a stylish homegrown party. In deba-bocho however, it is a very distinctive knife.
The main feature is the thick, heavy blade with an asymmetric section: on one side one of the “cheeks” is convex, on the other side it is flat. This makes it sharper and with a cut that can follow the curvature of the bones. The weight of the blade also allows it to be used to cut and carve through bone and cartilage with ease Beware, however, of twisting, which can nick it since the blade is very hard.
Because of its asymmetrical shape, the deba bocho is not ambidextrous; left-handed people must purchase one made especially for them.
The edge then is very protruding, spaced away from the axis of the handle.
These features make it ideal for filleting fish and cutting them into thin, precise slices.
Because of the asymmetry of the blade, special attention must be paid to the angle at which a deba is sharpened. When operating on the convex side the blade should be held at an angle, When sharpening the straight side the blade should be rubbed flat on the stone.
The name deba・出刃 (bocho is the word houcho・包丁, i.e., kitchen knife, modified to make it more pronounceable in the composite word), with its ideograms, literally means protruding blade. However, it is fairly common story, or joke, that it comes from the nickname of the blacksmith who first invented this particular shape, nicknamed deba because of the protruding teeth. Deba in fact can also have this meaning although it is written with different ideograms: 出歯.
These knives also have the typical shape that makes them immediately recognizable to most as “Japanese knives,” although less so than the more typical deba. They are characterized by a long, tapered blade, this is because the slice of fish for sushi and sashimi should be cut with a single movement of the blade, not by going back and forth as one would do to cut a slice of bread. This way the texture of the fish is not frayed, which would make it mushy and watery. To do this a long blade is essential, and it is also essential that it is not very thick so as to cause as little friction as possible between the meat and the steel.
1) Yanagiba・柳刃 o Shoububa・菖蒲刃
They literally mean the first “willow blade,” the second “gladiolus blade,” in that, as one can imagine, the shape of these knives resembles the leaves of the respective plants with which they are associated.They literally mean the first “willow blade,” the second “gladiolus blade,” in that, as one can imagine, the shape of these knives resembles the leaves of the respective plants with which they are associated.
Similar to yanagiba, but with a squarer tip.
Literally the mullet cutter. It is a “bonsai” yanagiba, ideal for filleting and cutting small fish.
The na-kiri is also quite exotic in features though less noble and elegant. The shape is rather squat and square. Its use is in fact more plebeian dealing mainly with the cutting of vegetables. Variations on the style of the na-kiri are the Kanto-style Edogata (the Tokyo region) and the Kansai-style Kamagata (the Osaka region), which are actually almost identical except to the most experienced eyes.
Another fundamental knife is the Santoku. The term literally means “the three virtues.” It is the all-purpose knife, which can be used well for cutting meat, fish and vegetables. The three virtues precisely. The santoku tends to be sharper than the debabocho but also has a thinner blade. It is probably the most versatile knife of all those that can be found in a Japanese knife shop, perhaps the first one to approach for novices to “really sharp cutting.”
The “spirit” of Japanese knives
The animism with which Shinto spirituality is imbued suggests that in everything, particularly in an object we use on a daily basis, so much spiritual energy accumulates that it almost takes on a soul. Knives long used by ordinary kitchen enthusiasts or real professionals, at the end of their careers, when they are now reduced to stumps from frequent sharpening, are taken to the temple where a kind of real funeral ritual is performed. The way many of these knives cut is something sometimes suggests that they are endowed with a will of their own, which can be quite sadistic in the way they treacherously pounce on the fingers of those who use them without due care. It is striking how unaccustomed to cooking the Japanese are to knives.
To conclude we post the site of one of the oldest Japanese knife stores. It is located in Kyoto and was apparently founded more than 400 years ago by a master sword smith. Unfortunately, it is only in Japanese, but you can enjoy the pictures. www.aritsugu.jp